Mobile system and method for characterizing radiation fields outdoors in an extensive and precise manner

ABSTRACT

A mobile measuring arrangement for precise characterization of large area radiation fields includes a hovering and remotely controllable platform which includes a measuring probe and at least one attitude and position determining arrangement.

The present invention relates to an method and apparatus for the highlyaccurate characterization of radiation fields.

The evaluation of radiation fields is indispensable in many areas, as,for example, in antenna near-field measuring technology. In near-fieldmeasuring, which is preferably used for antennas in the frequency rangefrom approximately 0.5 to 20 GHz, the immediate electromagnetic nearfield of an antenna is measured and is converted by means of anear-field (NF) to far-field (FF) transformation into the far field bymeans of the Fast Fourier Transformation (FFT). The advantage ofmeasuring the near field of an antenna lies in the compact dimensions ofthe necessary antenna measuring systems, which heretofore have almostexclusively been integrated into stationary measuring chambers.

In contrast to near-field measuring systems, there are also far-fieldmeasuring systems. However, due to their dimensions, these are exteriorsystems, and are always stationary devices. also, they are considerablymore prone to error as a result of reflections from the environment,terrain formations, buildings, etc.

Another advantage of the near-field measuring technique is that, as aresult of a near-field recording, all far-field sections can becomputed, while the once measured far-field sections are fixed and theantenna has to be measured again for additional far-field sections at alater point in time.

In accordance with the scanning theorem, the near field is scanned in<λ/2 intervals, and the entirety of the electromagnetic radiationemitted by the antenna must be detected, down to approximately −45 db,because the totality of these measuring points has an influence on eachindividual computed far-field point.

For measuring the radiation fields of omnidirectional antennas,spherical scanners are usually used, which scan the near field of theantenna to be measured on a spherical surface. In the case ofdirectional antennas, the high-expenditure spherical scanners may beeliminated, as long as all radiation fractions down to approximately −45db can be detected on a cylinder surface or on a planar surface. Sincedirectional antennas (parabolic antennas) are mainly used, for example,in telecommunications, the selection in this field usually leads tocylindrical near-field measuring systems or planar systems.

In the NF to FF transformation, in addition to the amplitude values ofthe individual measuring points, phase information is also used.Therefore, a scanner, , should be able to scan a spherical surface, acylinder or a planar surface by means of a measuring probe as nearlyideally as possible, because the NF to FF transformation ismathematically based on this ideal case. Error contributions by thescanner of a near-field measuring system should not exceed a deviationof λ/50 from the ideal contour.

Thus a scanner accuracy of 3.0 mm, at f=2.0 GHx and a phase accuracy ofλ/50 are necessary. If ground station antennas with an antenna diameterof, for example, 14 mm are to be measured by means of a planar measuringsystem, this degree of accuracy must be achieved on a surface of atleast 20 m×20 m.

For use with radar systems, near-field scanners should be as invisibleas possible. This is of course contrary to the normal mechanicalstructures required for such scanners, and as a rule can be achievedonly by the use of corresponding absorber coverings.

In order to obtain a maximum of phase accuracy of the measurement, datarecording should be recorded for of all measuring points as rapidly aspossible in order to minimize temporal phase drifts as much as possible.

Based on the above-mentioned example, with a surface to be scanned of 20m×20 m and a measuring point distance of 75 mm, an array of 267measuring points in width and 267 measuring points in height of theantenna, results in a total of at least 71,289 measuring points. A roughestimate shows that it would require unacceptable expenditures to driveto each of the measuring points, so that measuring must take placeduring the drive while passing the measuring position. At a scanningspeed of 100 mm/sec., data recording would therefore requireapproximately 15 hours.

From Stehle et al., “Reledop: A Full-Scale Antenna Pattern Measurement”L.E.E.E. Trans. On Broadcasting, Volume 34, No. 2, June 1988 (1988/06,Pages 210-220 YP 000054225 New York, US) and also Henβ,“Hubschrauber-Messung” NTZ Nachrichtentechnische Zeitschrift, Volum 40,No. 4, April 1987 (1987/04, Pages 258-261, YP-002168218) Berlin, Del.),it is known to arrange probes by means of a pilot-controlled helicopterwith the interposition of a long trail rope or a telescopic rod in afield to be measured. The use of a real helicopter and the interpositionof long trail ropes or telescopic rods, however, do no permit highlyaccurate measuring, and particularly no highly accurate positioningwithin the field to be measured.

It is an object of the present invention to provide an method andapparatus for a highly accurate evaluation of radiation fields, by meansof which highly accurate and large-surface measurements of radiationfields can be carried out at relatively low expenditures, particularlyin the exterior region.

This an other objects and advantages are achieved by the measuringarrangement (particularly a mobile measuring arrangement) for thealignment/position and/or detection of electromagnetic characteristicsof devices for/with the] emission of radiation fields according to theinvention, which includes a remotely-controllable measuring device thatcan hover, and has a measuring probe for detecting the targeted signal,as well as at least one device for determining the attitude and positionof the measuring device.

For determination of the attitude and position, position determinationsystems are preferably arranged in the vicinity of the emission device,in the form of position receivers/antennas that are provided in adefined position relative to the hovering device.

In the measuring device according to the present invention, preferably ahighly accurate global, non-terrestrial position determination system(such as the GPS) is used as the position determination system.

Furthermore, it is preferred that the position receiver/antenna of thesystem for measuring the site, the position and the attitude, isarranged on the measuring probe. In order that the electromagneticmeasurement conform as accurately as possible to the positiondetermination or alignment of the emitting device, the phase center ofthe measuring probe should be situated as close as possible to theposition receiver/antenna.

Furthermore, the emission device is preferably an antenna and, morespecifically, a parabolic antenna or an array antenna.

In addition, the measuring arrangement may be include a combination ofthe position receiver/antenna, a compass, a device for measuring inertiaforces, and one or more rotation sensors for determining and controllingthe attitude of the hovering device. To the extent that it may benecessary in a special application, other components can be added.

According to another feature of the measuring device has a plurality ofspatially separated position receivers/antennas. This permits the use ofa differential method for determining the position and attitude of thehovering device.

In a further embodiment of the measuring arrangement according to theinvention, an additional position receiver/antenna is provided as areference on the ground in the area of the emission device. This permitsthe use of a differential method for determining the position andattitude of the hovering device.

In a measuring arrangement constructed in this manner, direct visualcontact is not required between a ground station (at which, for example,the measuring equipment for processing the data supplied by themeasuring probe, as well as devices for controlling the hoveringmeasuring device can be provided) and the receiver. This may be anadvantage, particularly in the case of spherical scanning contours.

The position receivers/antennas and/or the measuring probe on thehovering device can advantageously be arranged in such a manner thatangular adjustment, swivelling or stabilization of the measuring probeis possible (in order, for example, to ensure a correct alignment,independent of an inclined position of the hovering device such as ahelicopter, even under the effect of wind.) In particular, stabilizationfor small position and angle deflections can be provided which, takingthe relative position of the emission device. This stabilization and/orpositioning can advantageously also interact with the measuring controlcircuit, so that a corresponding tracking can be displayed. As a result,a tolerances can be compensated, and therefore the individualmeasurements can be accelerated.

In another embodiment of the measuring arrangement according to theinvention, devices may be provided on the measuring probe for detectingthe signal, hovering in front of the emission device. The relativemomentary measuring position of these devices is detectable by at leastone geodetic instrument which is equipped with a device for emitting adefined optical signal, a device for receiving an optical signal, and adevice for reflecting the defined optical signal of the geodeticinstrument at the position to be measured. The reflecting device may be,for example, a spherical reflection surface, so that the reflection ofthe defined optical signal is reduced to a point for the viewer, and/orspherical reflection surfaces may be provided in a defined relativeposition with respect to the hovering device and/or the measuring probe.

The reflection surface may be part of a metal-coated sphere.

According to a further embodiment of the invention, the geodetic devicefor receiving an optical signal may be provided with a concave primarymirror, a convex secondary mirror and a detector device sensitive in twodimensions (such as a position diode) for generating a reading signal.As an alternative to the mirrors, other optical systems, such areflectors/refractors can also be used.

According to yet another embodiment of the invention, the secondarymirror may be placed essentially in the focus of the primary mirror,with the detector device placed opposite the secondary mirror in thearea of the primary mirror, preferably behind an opening in the primarymirror, through which the reflected optical signal passes which isfocussed in the secondary mirror.

Likewise, two geodetic instruments are preferably assigned to eachreflection device, so that a cross bearing is permitted.

The optical signal emitted by the geodetic instrument is preferably alaser beam, particularly a power-adjustable and/or modulable laser beam,and is provided with highly accurate angle-position encoders in theazimuth and in the elevation, for the dynamically accurate detection ofthe bearing angles with respect to the respective reflector. Forexample, when two laser beams are used, they can be modulated with adifferent frequency, permitting identification of the reflected signal.Also, in a particularly preferred embodiment, the power adjustingcapability is provided as a function of the distance between the lasersource reflector and the detector device. In this manner damage to thediode due to excessive laser irradiation can be avoided. It was found tobe particularly advantageous to use a semiconductor laser as the laserbeam, so that modulation can be represented as an alternative or in asupporting manner also by frequency filters.

In this case, this measuring arrangement is preferably constructed suchthat three of the above-mentioned arrangements are provided, with threereflection surfaces in a defined relative position on the hoveringdevice.

The measuring arrangement itself can detect electromagneticcharacteristics in a manner that is known per se. Normally a measuringprobe is used for this purpose. Thus, a reciprocal relationship can beachieved between the electromagnetic measurement, the measuring siteand/or the position of the radiating device. As a result of the highlyaccurate relative determination of the three parameters—position, fieldand generating of the field—, it is possible in a simple manner to carryout a plurality of highly accurate measurements, in which case themeasuring probe can be operated, for example, by using the initiallydescribed near-field measuring technique.

Furthermore, one of the spherical reflection surfaces is preferablyarranged on the measuring probe. In order to maximize the degree ofconformity between the electromechanical measurement and the positiondetermination or alignment of the radiating device, the phase center ofthe measuring probe should be situated as close as possible to thecenter point of the spherical reflection surface. Optimum precision isobtained when the center point of the sphere and the phase centercoincide. In addition, the emission device preferably is an antenna and,more specifically, a parabolic antenna or an array antenna.

In addition to the above-mentioned characteristics, the measuringarrangement according to the invention may include an autofocussingdevice for imaging the reflected laser beam, which speeds detection ofindividual measuring points, and increases their precision. It shouldalso be mentioned that also the relative position of the diode or thedetector device can be evaluated in the display area in order to furtherincrease the measuring accuracy.

The size and the mass of the hovering device is preferably small inrelationship to that of the emission device that is to be positioned,because objects in an electromagnetic field to be measured may result inconsiderable measuring errors. In order to meet this requirement, it isadvantageous to provide, for example, a miniature helicopter as ahovering device. However, other alternatives, such as controlledballoons, zeppelins, or similar devices, are also conceivable, whichpreferably are radio-controlled.

In addition to the measuring, the invention also provides a method forthe highly accurate evaluation of radiation fields, particularly formobile use and/or in the exterior region. The method advantagesaccording to the invention comprises the following steps:

1. positioning a hovering remotely-controllable measuring device in theradiation field, with a measuring probe for the detection of theradiation field at least one device for determining the attitude andposition of the measuring device;

2. determining the position and attitude of the measuring device; and

3. generating a measuring signal for characterizing the radiation field;and

4. transmitting of the measuring signal from the hovering part of themeasuring arrangement to a ground-side measuring instrument system.

According to the invention, the method can be further developed suchthat the coordinates of the systems can be determined in three spacialdimensions, and from these coordinates, position and the actual attitudeof all six degrees of freedom of the measuring device are dynamicallydetermined (particularly in real time).

Furthermore, the actual position and attitude (all six degrees offreedom) of the measuring device can be compared with the defineddesired position and attitude, and can be controlled in a closed-loopcontrol circuit during the controlling, stabilization or positioning ofthe measuring probe.

Finally, a person skilled in the art will understand that, although thepresent application addresses a radiating device, the invention can alsobe used in a reversal/supplementation in the case of a receiving systemor a field-alternating, particularly a reflecting device.

One decisive advantage of the measuring arrangement according to theinvention is that its mobility permits a complete and highly accuratecharacterization of radiation characteristics of large, usuallystationary antenna systems in the exterior region.

Additional advantages of the invention include:

a high positioning precision from approximately 2.0 mm to 50 m;

large positioning ranges of up to 100 m edge length of a cube;

high positioning speed <1.0 min over a positioning route of 10 m;

highly accurate detection of all 6 degrees of freedom of 0.5 mm and 1.0angular minutes at a distance of 50 m;

mobility;

lower installation expenditures; and

broad application spectrum (antenna measurements, radar backscatteringmeasurements, electromagnetic compatibility measurements, environmentalmeasurements, etc.)

Other objects, advantages and novel features of the present inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of an embodiment of a geodeticinstrument for position measuring;

FIG. 2 is a schematic lateral view of an embodiment of the measuringarrangement for the positioning by means of geodetic instruments;

FIGS. 3 to 5 are views of an embodiment of the hovering device accordingto the invention;

FIG. 6 is a top view of the measuring arrangement according to FIG. 2;

FIG. 7 is a frontal view of the measuring arrangement according to FIG.2;

FIG. 8 is a schematic representation of the regulating and controlconcept according to the invention;

FIG. 9 is a schematic lateral view of an embodiment of the measuringarrangement for the positioning by means of position determinationsystems;

FIG. 10 is a top view of the measuring arrangement according to FIG. 9;

FIG. 11 is a frontal view of the measuring arrangement according to FIG.9.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates an embodiment of an arrangement for the positionmeasuring, having two geodetic instruments 2, (here opticaltheodolites), each having a device 4 for emitting a defined opticalsignal 6 (here a laser beam), as well as a device for receiving anoptical signal 8, and a device 10 for the reflection of the definedoptical signal 6 of the geodetic instrument 2 at the position to bemeasured. The device 10 is formed here by a reflecting or metal-coatedsphere 10 so that the reflection of the defined optical signal 6 isreduced to a point 12 for the viewer.

As further illustrated in FIG. 1, for receiving the reflected opticalsignal 8 the geodetic device 2 is equipped with a concave primary mirror14, a concave secondary mirror 16 and a detector device 18 that issensitive in two dimensions, for generating a reading signal. Thesecondary mirror 16 is arranged in the focus of the primary mirror 14,and a detector device 18 is placed opposite the secondary mirror 16 inthe area of the primary mirror 14 behind an opening 20 therein. Thereflected optical signal 8 passes through the opening and is focussed inthe secondary mirror 16. In the illustrated embodiment, each geodeticinstrument 2 is equipped with highly accurate angle-position encodersand tracking drives in the azimuth and the elevation, for thedynamically accurate detection/tracking of the bearing angles to therespective reflector, by means of the detector device 18.

FIG. 2 shows an embodiment of a measuring arrangement for highlyaccurate alignment/positioning of a device for the emission of targetedradiation-type and/or wave-shaped signals, (here, a parabolic antenna22). In the illustrated embodiment, a device 24 is provided which isequipped with a measuring probe for detecting the signal of the antennas22, and hovers in front of the antenna. The position of this device 24can be detected by a number of arrangements for the position measuring,such as illustrated in FIG. 1. FIG. 2 shows six optical theodolites 2,the laser beams 6 originating from the latter being aimed at reflectorsfastened to the device 24 hovering in front of the antenna 22.

FIGS. 3 to 5 are more detailed views of the hovering device 24 of theembodiment according to FIG. 2. Here it is illustrated that a preferablyminiaturized helicopter is used which is provided with three devices 10for the determination of the attitude and position of the measuringdevice 24. These devices 10, which can be detected by systems fordetermining the attitude and position, are fastened to extension arms26, or to the measuring probe 28 for the detection of the antennasignal, in a defined position relative to the helicopter. They may, forexample, be metal-coated spheres 10, as described with reference to FIG.1, or position receivers/antennas 10 for position determination systems(not shown) available at the site of the emission device 22.

The miniature helicopter is used in the illustrated embodiment becauseit is suitable for taking up a stable hovering position in front of theantenna 22 to be measured. It also has a small mass in comparison to thelatter, so that virtually no measuring errors are generated as a resultof the helicopter, and can be controlled by means of simple knowntechnology. In order to further reduce measuring errors, a positioningand/or stabilizing device, (not shown) can be provided which representsa certain uncoupling with respect to the helicopter and permits analmost arbitrary position of the latter with respect to the radiatingdevice. When the helicopter is, for example, above the radiating device,the measuring probe should be essentially directed downward.

FIGS. 6 and 7 are a top view and a frontal view respectively of theembodiment of FIG. 2, identical elements having the same referencenumbers.

In measuring arrangement according to FIGS. 2 to 7 the positions(azimuth and elevation) of the laser reflectors 10, which are fastenedto the helicopter, are each determined by means of two of the highlyaccurate angle measuring devices 2. In this case, an automatic targettracking takes place based on the laser beam 6 emitted by the respectiveangle measuring device or optical theodolite 2, for example, by means ofa tracking device.

When several laser beams are used, it should be possible to distinguishthem from one another. For this purpose, modulable semiconductor lasersor lasers with frequency filters connected on the output side can, forexample, be used, so that each laser beam has separate specificcharacteristics which permit its identification.

Each laser beam 6 is reflected at one of the laser reflectors 10 mountedon the helicopter, and is imaged by the optical telescope 14, 16 in therespective angle measuring device 2, on the detector device 18 which issensitive in two dimensions. Any movement of the helicopter (and thus ofthe laser reflectors 10), causes a course indicating signal to begenerated, which is fed into a regulating circuit. The latter causes atracking by means of tracking drives (not shown), with regard to bothazimuth and elevation. Highly accurate azimuth and elevationangle-position encoders and in the (not shown) supply dynamicallyprecise bearing angles to the respective laser reflector 10. Since, asillustrated in FIGS. 2, 6 and 7, two angle measuring devices 2respectively 2 take a bearing with respect to the same laser reflector10, the coordinates of the respective laser reflector 10 can bedetermined in three spatial dimensions.

From the coordinates of the three laser reflectors 10, the actualposition and attitude (six degrees of freedom) of the helicopter 24 willthen be dynamically determined. This information is compared with agiven desired position desired attitude, and the helicopter iscontrolled in a closed-loop control circuit by means of the helicoptercontrol. In this manner, the helicopter or the measuring probe 28mounted thereto for detecting the targeted signal of the antenna 22 canbe positioned with the highest precision in all 6 degrees of freedom atheights of up to 100 m. The downlink from the helicopter 24 as thehovering device takes place according to known transmission concepts;coupling by way of a glass fiber arrangement freed of expansion faultsis preferred in addition to other possibilities. However, care should betaken that this results in no faults, such as a phase displacement.

FIG. 8 illustrates the regulating and control concept of the presentinvention. The angle measuring devices 2 are connected with positioncomputers 30 which compute the position of a respective reflector 10 inreal time. The position data determined in this manner are transmittedto the position and attitude computer 32 of the hovering device 24. Theactual values for the position and the attitude are fed into point 34,whereupon, at reference number 36, a desired/actual comparison takesplace with respect to the position and attitude, taking into account thedesired values 38 for the position and attitude originating from theapplication. On the basis of this comparison, correcting variables forthe helicopter control 40 are generated which are transmitted by way ofa remote control 42 to the helicopter 24.

FIG. 9 shows another embodiment of a measuring arrangement according tothe invention. (The same elements as in FIGS. 1 to 8 have the samereference numbers.) In this embodiment, a remotely-controllablehoverable measuring device 24 is equipped with a measuring probe 28 fordetecting the targeted signal, and with at least one positionreceiver/antenna 10 for position determination systems (not shown)available at the site of the emission device (antenna 22). A globalnon-terrestrial site determination system, such as the GPS, ispreferably used as the position determination system, by means of whichpositions above the earth surface can be determined with a relativelyhigh accuracy. Another stationary position receiver/antenna 44 isprovided at a ground station. The measuring device 24 is connected byway of a data link 42 with a ground station or the positionreceiver/antenna 44 provided there, which supplies a highly accuratereference position.

By means of the measuring arrangement according to the invention, areciprocal relationship can be achieved between the electromagneticmeasurement, the measuring site and/or the position of the radiatingdevice 22. As a result of the highly accurate relative determination ofthe three parameters—position, field and generating of fields—, it ispossible in a simple manner to implement a plurality of highly accuratemeasurements. The measuring probe 28 can thus be operated, for example,by using the near-field measuring technique.

It should be noted in this case that here the preferably miniaturizedhelicopter, as described with reference to FIGS. 3 to 5, is equippedwith three position receivers/antennas 10 for a navigation orpositioning system, such as the GPS, which are fastened to the extensionarms 26 or to the measuring probe 28 in a defined position to thehelicopter and to one another respectively. In order to maximize thedegree of conformity between the electromagnetic measurement and theposition determination or alignment of the radiating device 22, thephase center of the measuring probe 28 is situated very close to theposition receiver/antenna 10.

The provision of a plurality of spatially separated positionreceivers/antennas 10 on the miniature helicopter 24, as well as theadditional position receiver/antenna as reference on the ground in thearea of the emission device, permits the use of a different method forthe position and attitude determination, such as the DGPS of thehelicopter 24.

In the case of a measuring arrangement constructed according to thepresent invention, direct visual contact is not required between theground station 44 (at which, for example, measuring equipment may beprovided for the processing of the data supplied by the measuring probeas well as devices for controlling the hovering measuring device 24) andthe respective receiver 10. This may be an advantage, particularly inthe case of spherical scanning contours.

In order to further reduce measuring errors, a positioning and/orstabilizing device (not shown) can be provided which represents acertain uncoupling with respect to the helicopter and permits an almostarbitrary position of the latter with respect to the radiating device.When the helicopter is, for example, present above the radiating device,the measuring probe 28 should be essentially directed downward.

FIGS. 10 and 11 are a top view and a frontal view respectively of thearrangement of FIG. 9.

In measuring arrangement according to FIGS. 9 to 11 the positions of theposition receiver/antenna 10, which are fastened to the helicopter 24,as well as of the position receiver/antenna 44 of the ground station 44,are determined in each case. From this information the respectivemomentary position and attitude of the helicopter 24 can be computedpreferably in real time.

By the use of a corresponding navigation or positioning system, such asthe GPS, the coordinates of the respective position receiver/antennas 10can be determined. From the coordinates of the three positionreceivers/antennas 10 as well as the position receiver/antenna 44, theactual position and the actual attitude (all six degrees of freedom) ofthe helicopter 24 will then be dynamically determined. This informationis compared with the defined desired position and desired attitude andis controlled in a closed-loop control circuit by means of thehelicopter control. In this manner, the helicopter or the measuringprobe 28 mounted thereon for detecting the targeted signal of theantenna 22 can be positioned with the greatest accuracy in all 6 degreesof freedom. The downlink 42 from the helicopter 24 as a hovering devicetakes place according to known concepts, in which case the transmissionof the measuring signals for the characterization of the radiation fieldcan be implemented, for example, by means of a glass fiber arrangementfrom which the expansion and temperature errors have been removed. Careshould, however, be taken that no inadmissible errors, such has phasedisplacements, occur as a result.

The regulating and control concept of the present invention providesthat position computers compute the respective position of a positionreceiver/antenna 10 as nearly as possible in real time. The positiondata determined in this manner are transmitted to a position computer ofthe helicopter 24. The actual values for the position and attitude arefed into the position computer of the helicopter 24, whereupon adesired/actual comparison takes place with respect to the position andattitude while the desired values for the position and attitude aretaken into account which originate from the application. On the basis ofthis comparison, operating variables for the helicopter control aregenerated which are transmitted by remote control to the helicopter 24.

By means of the arrangement according to the present invention, highpositioning accuracy can be achieved in a simple and advantageousmanner. Also, high positioning speeds and a highly accurate detection ofall 6 degrees of freedom and most importantly, a highly accuratecharacterization of radiation fields being permitted. In this case, thearrangement and the method are suitable for applications in the exteriorregion, ensure mobility, require low installation expenditures and havea broad application spectrum (antenna measurements, radar backscatteringmeasurement, electromagnetic compatibility measurements, environmentalmeasurements, etc.) However, due to their mobility, they mainly permit ahighly accurate and large-surface measuring and characterization ofradiation fields in the exterior region.

In addition to the illustrated embodiment, a combination of individualelements of the respective embodiments with one another is alsoconceivable.

The foregoing disclosure has been set forth merely to illustrate theinvention and is not intended to be limiting. Since modifications of thedisclosed embodiments incorporating the spirit and substance of theinvention may occur to persons skilled in the art, the invention shouldbe construed to include everything within the scope of the appendedclaims and equivalents thereof.

What is claimed is:
 1. A measuring arrangement for evaluatingelectromagnetic characteristics of an apparatus for emission orreflection of radiation fields, said measuring arrangement comprising: aremotely controllable measuring device which can hover at a spatialposition; a measuring probe arranged on the measuring device, fordetecting a targeted signal propagated from the apparatus; at least oneelement arranged on the measuring device for determining attitude andposition of the measuring device; and systems for determining theattitude and position of the measuring device; wherein the element fordetermining attitude and position can be detected by the systems fordetermining the attitude and position; and size and mass of themeasuring device are small in relation to the apparatus to be evaluated.2. A measuring arrangement according to claim 1, wherein: the systemsfor determining the attitude and position are position are arranged atthe site of the emission device; and the at least one element fordetermining attitude and position comprises at least one positionreceiver/antenna, disposed in a defined position relative to themeasuring device.
 3. The measuring arrangement according to claim 2,wherein a global non-terrestrial site determination system is used asthe position determination system.
 4. The measuring arrangementaccording claim 1, wherein the at least one element for determiningattitude and position comprises a position receiver/antenna arranged onthe measuring probe.
 5. The measuring arrangement according to claim 4,wherein the position receiver/antenna is arranged in the directproximity to the phase center of the measuring probe.
 6. The measuringarrangement according to claim 4, wherein: the measuring device furthercomprises a compass, a device for measuring inertial forces and/oraccelerations, and at least one rotation sensor, for determination andcontrol of the attitude of the hovering measuring device.
 7. Themeasuring arrangement according claim 4, wherein the measuring devicehas a plurality of position receivers/antennas arranged thereon, atspatially separated positions.
 8. The measuring arrangement according toclaim 4, wherein an additional position receiver/antenna is provided asa reference on the ground in the area of the emission device.
 9. Themeasuring arrangement according to claim 1, wherein: the systems fordetermining attitude and position comprise at least one geodeticinstrument, which is equipped with a device for emitting a definedoptical signal and a device for receiving an optical signal, includingat least one spherical reflection surface for reflection of the definedoptical signal of the geodetic instrument at a position to be measured,so that the reflection of the defined optical signal is reduced to apoint for a viewer; and the spherical reflection surface is provided ina defined position relative to the measuring device.
 10. The measuringarrangement according to claim 9, wherein the reflection surfacecomprises at least a part of a metal-coated sphere.
 11. The measuringarrangement according to claim 9, wherein the device for receiving anoptical signal includes a concave primary mirror, a convex secondarymirror and a detector device that is sensitive in two dimensions forgenerating a reading signal.
 12. Measuring arrangement according claim11, wherein: the secondary mirror is placed approximately at a focus ofthe primary mirror; and the detector device is placed opposite thesecondary mirror, in proximity to the area of the primary mirror. 13.The measuring arrangement according to claim 12, wherein the detectordevice is placed behind an opening in the primary mirror.
 14. Themeasuring arrangement according to claim 11, wherein the reflectionsurface comprises at least a part of a metal-coated sphere.
 15. Themeasuring arrangement according to claim 9, wherein two geodeticinstruments are assigned to each reflection device, whereby a crossbearing is permitted.
 16. The measuring arrangement according to claim9, wherein the optical signal emitted by the geodetic instrument is alaser beam.
 17. The measuring arrangement according to claim 16, whereinthe laser beam is at lease one of power-adjustable and modulable. 18.The measuring arrangement according to claim 9, wherein the geodeticinstrument has precision azimuth elevation angle-position encoders, fordynamically accurate detection of the bearing angles with respect to arespective reflection device.
 19. The measuring arrangement according toclaim 9, wherein three spherical reflection surfaces are provided forthe reflection of the defined optical signal of the geodetic instrumentat a position to be measured.
 20. The measuring arrangement according toclaim 9, wherein one of the spherical reflection surfaces is arranged onthe measuring probe; and a phase center of the probe coincidessubstantially with a center point of the spherical reflection surface.21. The measuring arrangement according to claim 1, wherein themeasuring probe is constructed for near-field measuring.
 22. Themeasuring arrangement according to claim 1, wherein, the measuringdevice is a remote-controllable miniature helicopter.
 23. The measuringarrangement according to claim 1, wherein the measuring device is aremote-controlled balloon.
 24. The measuring arrangement according toclaim 1, wherein the measuring device is a remote-controlled zeppelin.25. The measuring arrangement according to claim 1, wherein themeasuring device is a remote-controlled airplane.
 26. A method for thecharacterization of radiation fields, comprising: hovering aremote-controllable measuring device in the radiation field, saidmeasuring device having a measuring probe for detection of the radiationfield, and at least one element for determining attitude and position ofthe measuring device, which element can be detected by systems fordetermining the attitude and position; determining position and attitudeof the measuring device, said measuring device generating a measuringsignal for characterizing the radiation field; and transmitting themeasuring signal from the hovering measuring device to a ground-sidemeasuring instrument system.
 27. The method according to claim 26,wherein: spatial coordinates of the at least one element for determiningposition and attitude are determined; and based on said coordinates,actual position and attitude of the measuring device in six degrees offreedom is dynamically determined.
 28. The method according to claim 27,wherein: the actual position and attitude of the measuring device arecompared with a defined desired position; and attitude and position arecontrolled in a closed-loop control circuit by control of the measuringdevice.
 29. The method according to claim 27, wherein actual positionand attitude are determined in real time.